Continuous flow pasteurizer



H. l. SOUTHERWICK CONTINUOUS FLOW PASTEURIZER March 30, 1948.

Filed July 15, 1944 3 Sheets-Sheet l ill III I III"!!! llllll ll 3W Him/0 1'. 501226 292" mak March 1948. H. 1. SOUTHERWICK CONTINUOUS FLOW PASTEURIZER Filed July 15, 1944 3 Sheets-Sheet 2 gjkm March 30, 1948. H. 1. SQUTHERWICK 2,438,532

CONTINUOUS FLOW PASTEURIZER Filed July 13, 1944 3 Sheets-Sheet 3 ANMETER GAL/BRA 7'50 nv DEGREES 0F TEMPERATURE a4 H 1 E Ham/01 fiauih rwzzk 37 ggwmgm Patented Mar. 30, 1948 CONTINUOUS FLOW PASTEURIZER Harold I. Southerwick, to The Do All Compa nership Des Plaines, Ill., assignor ny, Des Plaines, 111., a part- Application July 13, 1944, Serial No. 544,795

4 Claims. 1

This invention relates to pasteurizers for liquids, and has as its general object to provide a pasteurizer in which the liquid to be pasteurized flows continuously therethrough,

Another object of this invention is to provide a p-asteurizer of the character described wherein the necessary elevated temperature is obtained by passing an electric current through the liquid to be pasteurized.

Another object of this invention is to provide a continuous flow pasteurizer having spaced electrodes connected in an electric circuit and means for causing the liquid to be pasteurized to flow between the electrodes so that current flowing through the liquid from one electrode to the other effects the necessary heating of the liquid.

Another object of this invention is to provide means for controlling the flow of liquid through the pasteurizer unit so as to have the liquid flow therethrough at a rate not to exceed that necessary to insure all of the liquid being heated to the required temperature.

In this connection, it is another object of this invention to provide novel control means for regulating the flow of liquid through the unit wherein the actuation of the control means is governed by the magnitude of the electric current flowing through the liquid from one electrode to the other.

Another object of this invention is to provide a continuous flow pasteurizer wherein the incoming liquid is preheated by contact with the walls of the passages through which the pasteurized liquid flows.

Another object of this invention is to provide a continuous flow pasteurizer wherein the incoming cool liquid flows over the exterior inactive surfaces of the electrodes to cool the same and prevent objectionable overheating thereof and at the same time further preheat the liquid.

To control the flow of liquids through the unit this invention incorporates a valve within one of the liquid passages, and control mechanism for the valve on the exterior of the passage.

Another object of this invention thus resides in the provision of novel means for precluding leakage of fluid from the passage and at the same time enable free actuation of the valve from the exterior of the passage.

Another object of this invention is to provide means for indicating at all times the temperature of the liquid in the pasteurizing zone.

Still another object of this invention is to provide a continuous flow pasteurizer especially Well adapted for use in dairies and which is so designed and constructed as to be readily disassembled for cleaning and inspection.

A further object of this invention is to provide a continuous flow pasteurizer of the character described, which is exceedingly simple in design.

With the above and other objects in view, which will appear as the description proceeds, this invention resides in th novel construction, combination and arrangement of parts substantially as hereinafter described, and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawings illustrate one complete example of the physical embodiment of the invention, constructed in accordance with the best mode so far devised for the practical application of the principles thereof, and in which:

Figure 1 is a view in front elevation of a complete pasteurizing unit constructed in accordance with this invention;

Figure 2 is a view partially in front elevation and partially in longitudinal section of the pasteurizer per se;

Figure 3 is a side view of the pasteurizer;

Figure 4 is a cross sectional view through Figure 2 on the plane of the line 4-4;

Figure 5 is a cross sectional view through Figure 2 on the plane of the line 5-5;

Figure 6 is a cross sectional view through Figure 2 on the plane of the line 6-6; and

Figure 7 is a diagrammatic view illustrating the electrical circuit of the pasteurizer unit.

Referring now particularly to the accompanying drawings in which like numerals indicate like parts, the numeral 5 designates a tank or container for liquid to be pasteurized and into which the liquid is deposited in any suitable manner. In the present instance this tank is mounted on legs 6 but any suitable manner of supp0rting the tank above the floor may be used.

Suspended beneath the tank 5 is the pasteurizer unit l of this invention. By thus suspending the pasteurizer unit beneath the tank the liquid to be pasteurized flows by gravity down into it through an inlet 8 and after being pasteurized is conducted from the unit through a discharge line 3. It is, of course, to be understood that the pasteurizer unit need not be suspended beneath a supply tank as shown in Figure 1 and that any means may be employed to conduct the liquid to be pasteurized to the inlet 3 of the unit.

Essentially the pasteurizer consists of a pair of spaced parallel electrodes W and H and a housing structure indicated generally by the numeral I2 coacting with the electrodes to define an inner vertical passage I3 bounded at two opposite sides by the electrodes and two outer liquid passages I4 each bounded at one side by an electrade. The inner and outer passages are connected at one end (in this instance at the bottom) but not at the other end.

An inner box-like chamber I5 in open communication with the top of the inner chamber I3 and having a discharge nipple I6 passing through a, wall of the housing I2 and connected to the discharge pipe 9 provides for the discharge of. the pasteurized liquid from the inner chamber, and shuts off the inner passage from the outer passages at the upper end of the unit. 7

It is to be observed that the chamber I5 has a relatively thin Wall and that it is located di-' rectly beneath the inlet 8. Consequently, raw liquid to'be pasteurized flows over the'thin walled chamber I5 to reach the two outer passages I l and in so doing becomes preheated; The raw liquid is further preheated by contact with the inactiveouter' sides of the two electrodes as it flows down through the twoouter passages I4;

Obviously, the liquid flowing down through the passages I4 enters the inner passage at its lower end and flows upward between the electrodes I3 and II. In sodoing the liquid is heated by electric current flowing through it from one electrode to the other.

In order to'assure heating the liquid to the proper temperature its rate of flow through'the pasteurizer unit is controlled. This control is achieved through the provision-of a, valve II regulating the flow from "the inner passage 13 into the chamber IS. The stem I8 of this valve extends down through the'inner chamber and out through the bottom wall I9 of the housing I2.

At'its passage through the wall -I 9 novel means, to be hereinafter described, provide a fluid tight seal between the stem I8 and the wall I9 without interferring with the free actuation of the ceeds at a rather steep gradient. For a given change in milk temperature there is a corresponding change in electric current flowing through the milk, and in view of the steep angle of the curve a small change in temperature results in a large change in current flow.

'It is, therefore, possible to control the liquid flow within close limits.

Inasmuch as the coil of the solenoid is connected in series circuit with the electrodes, the adjustment of the valve efiectecl thereby is proportional to the temperature of the milk. Hence, the milk will be allowed to flow through the unit at a rate commensurate with the ability of the electric current to heat it to the required temperature.

While the invention is especially well adapted for the pasteurization of milk, it will be readily apparent that any liquidhaving similar electrical resistance characteristics can'successfully be handled by the apparatus.

The temperatureto which the milk or other liquid being pasteurized'is heated within the inner chamber is indicated by the ammeter 26, the dial of which is calibrated in degrees of temperature.

The electrodes are preferably in the form of bars of carbon 'with metal inserts embedded therein. The terminals of the electrodes which pass through the bottom wall of the housing are threaded into the lower ends of the metal inserts. The upper ends of the inserts have screws 29 threaded therein. These screws pass through a transverse plate 39 to hold the upper ends of the electrodes in position.

stem. Below the bottom wall I9 the-valve stem is connected to the armature 20 of a current responsive solenoid '2I. r

The coil of the solenoid, as specifically shown in Figure 7', is connected in series circuit with the electrodes, one side of the supply line 22.being connected to one end of the coil as at 23 and the otherend of the coil'being connected to the terminal 24 of one of the electrodes. The circuit is completed through the liquid between the electrodes, the other electrode having its terminal 25 connected to one side of an ammeter 26 interposed in the other side 21 of the supply line.

It is to be observed that movement of the armature 29in response to energization of the solenoid lifts the valve l'I-oif its seat to increase the flow of liquid through the unit; and that a spring 28 acting downwardly on the armature opposes the action of the armature. Thus, through proper choice of spring tension it is possible to regulate the position-of the valve as desired. An increase in the magnitude of the current flowing through the liquid results in opening of the valve while a decrease of the magnitude of the current flowing through the liquid results in movementof the valve towards closed position.

By experiment it has been determined that the electrical characteristics of milk are such that its resistance to the passage of an electric current therethrough decreases as its temperature rises and that the curve depicting this relationship is substantially a straight line which pro- The plate 39 has openings 3! in line with the outer passages I4 and has a metal ferrule 32 secured therein in line with the inner passage I3. This metal ferrule provides the seat for the valve I1 and also provides means for attachin the chamber I5. To this endthe ferrule has its upper end threaded to be received in a tapped hole in the bottom of the chamber I5.

An insulating lining or gasket 33'covers the top face of the plate 39to provide electrical insulation between the bottom of the chamber I5 and the heads of the screws 29,-as it is preferable from the standpoint of heat transfer to form the chamber I5 of metal. i

The housing I2 comprisesthree parts 'or sections, namely a middle frame member 34 and two outer side wall sections efi'and 36. As shown in Figures 4 and 5, the side wall sections 35 and 36 have their inner faces rabbeted to receive the middle frame section 34 and the electrodes I9 and II. Through bolts 37 or studs 'tapped'into the middle frame section 34 hold the three parts of the housing together in a manner permitting ready disassembly, and to assure fluid tight junctures suitable'gaskets are provided at the meeting surfaces of the sections.

The side wall sections 35 and 36 have window openings 38 to expose transparent panels 39 which coact with the electrodes'to complete the inner chamber I3. These transparent panels are seated in rabbets in the side edges of the electrodes so that the assembled electrodes and transparent panels present flush surfaces against which the side wall panels 35 and 3B engage. Through the provision of these transparent panels it is possible to visually observe the milk or other liquid as it is being pasteurized.

. The side wall sections 35 and 36 are preferably bulged out at their upper ends to permit the chamber I5 to be quite large as shown in Figure 6. This provides a largesurface area heated by the pasteurized liquid leaving the unit with which the incoming liquid contacts, the side wall section 36 having the nipple 16 passing therethrough.

The three parts or sections of the housing are preferably formed of thermoplastic or other suitable insulating material to obviate the need for insulating the electrodes therefrom; but if it is desired to have the housing made of metal it is only necessary to provide suitable electrical insulation between the side wall sections and the electrodes and to in other ways insulate the electrodes so that the only possible current path from one to the other is through the liquid in the inner passage l3.

The fluid tight seal in the bottom wall is of the housing through which the valve stem ill passes comprises a cup-like member Mi of rubber or other suitable elastic material having a rounded bottom and an outwardly flared or conical shaped open end. The round bottom of the cup member is secured to the valve stem by being clamped between a nut 42 on the stem and the rounded end of an extension 4! which actually passes through the bottom of the wall I 9 and projects beneath the same to be secured to the armature 20.

The hole 43 in the bottom wall is tapered or conical to receive the correspondingly shaped end portion of the rubber cup member. The tapered end 44 of a mounting bushing 45 in which the armature slides projects into the cup member to clamp its conical wall portion to the edge of the hole, the mounting bushing being held in place by the nuts threaded onto the terminals of the electrodes.

The compression spring 28 which urges the valve l'i towards its closed position is confined between the top of the armature and the end wall of the bushing 45; and the entire solenoid structure, including the bushing, is enclosed within a protecting housing 46 consistin of two similar half sections held together by through bolts 4! and supported on the underside of the bottom wall Is by interengaging tongue and groove connections 48 on the bushing 45 and the housing sections.

From the foregoing description, taken in connection with the accompanying drawings, it will be readily apparent to those skilled in the art that this invention provides an exceedingly simple and eifective continuous flow pasteurizer.

What I claim as my invention is:

1. A pasteurlzer for liquids comprising: a substantially elongated housing; a pair of spaced electrodes in said housing extending lengthwise thereof and cooperating with the side walls of the housing to form a central liquid passage between the electrodes in which the liquid to be pasteurized is treated and two outer pre-treatment passages one at each side of the central passage with each of said outer passages separated from the central passage by one of said electrodes, said electrodes terminating short of one end of the housing so as to cause all of said passages to be communicated with each other at said end of the housing; means common to both of said electrodes for closing olf the central passage from said outer passages at the opposite end of the housing, said central passage having an outlet at said opposite end of the housing through which liquid traveling through the central passage between said electrodes from the first designated end of the housing to the opposite end thereof discharges after being heated by the flow of electric current therethrough from one electrode to the other; and means connecting with said outer passages at said opposite end of the housing for simultaneously conducting liquid into said outer passages to thereby assure travel of the liquid the length of the housing prior to simultaneous entrance of the streams of liquid from said outer passages into the central passage for heating thereof.

2. A pasteurizer for liquids comprising: a substantially elongated housing; a pair of spaced electrodes in said housing extending lengthwise thereof and cooperating with the side walls of the housing to form a central liquid passage between the electrodes in which the liquid to be pasteurized is treated and tWo outer pre-treatment passages one at each side of the central passage with each of said outer passages separated from the central passage by one of said electrodes, said electrodes terminating short of one end of the housing so as to cause all of said passages to be communicated with each other at said end of the housing; means common to both of said electrodes for closing off the central passage from said outer passages at the opposite end of the housing, said central passage having an outlet at said opposite end of the housing through which liquid traveling through the central passage between said electrodes from the first designated end of the housing to the opposite end thereof discharges after being heated by the flow of electric current therethrough from one electrode to the other; means connecting with said outer passages at said opposite end of the housing for simultaneously conducting liquid into said outer passages to thereby assure travel of the liquid the length of the housing prior to simultaneous entrance of the streams of liquid from said outer passages into the central passage for heating thereof; and means for controlling the rate of flow of liquid through said passages.

3. A pasteurizer for liquids comprising: a substantially elongated housing; a pair of spaced electrodes in said housing extending lengthwise thereof and cooperating with the side walls of the housing to form a central liquid passage between the electrodes in which the liquid to be pasteurized is treated and two outer pre-treatment passages one at each side of the central passage with each of said outer passages separated from the central passage by one of said electrodes, said electrodes terminating short of one end of the housing so as to cause all of said passages to be communicated with each other at said end of the housing; means common to both of said electrodes for closing oil the central passage from said outer passages at the opposite end of the housing, said central passage having an outlet at said opposite end of the housing through which liquid traveling through the central passage between said clectrodes from the first designated end of the housing to the opposite end thereof discharges after being heated by the flow of electric current therethrough from one electrode to the other; means connecting with said outer passages at said opposite end of the housing for simultaneously conducting liquid into said outer passages to thereby assure travel of the liquid the length of the housing prior to simultaneous entrance of the streams of liquid from said outer passages into the central passage for heating thereof; valve means for controlling the flow of liquid through said passages; and current responsive control means for the valve connected in series with said electrodes whereby the magnitude of the current flow through the liquid in the inner passage determines the position of the valve.

4. A pasteurizer for liquids comprising: a pair of electrodes each consisting of a metal rod embedded in a carbon bar; a housing structure clamped against the sides of said carbon bars to coact therewith in the formation of an inner liquid passage bounded on two sides by the faces of said electrodes and two outer liquid passages each bounded at one side by the back of one electrode, said electrodes terminating short of one end of the housing structure so as to cause all of said passages to be connected at said end of the housing structure; a chamber having communication with the inner passage adjacent to the opposite end of the housing structure to receive pasteurized liquid from the inner passage and to close ofi the inner passage from the outer passages at said opposite end of the housing structure; an outlet for pasteurized liquid leading from said chamber; an inlet for liquid to be pasteurized adjacent to said chamber and. opening to the outer passages at said opposite end of the housing structure so that liquid to be pasteurized flows over the chamber to and through said outer passages in streams simultaneously entering the inner passage at said first designated end of the housing structure where all of said passages connect with each other; and means for connecting the electrodes in an electric circuit so that an electric current flows through the liquid in the inner passage from one electrode to the other.

HAROLD I. SOUTHERWICK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

